<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
   
    <script>
        /*
        转换为字符串
        */
      let sum=100;
      console.log(sum.toString());
      console.log(String(sum));
      console.log(sum+"");

      /*
        转化数字
      */
    let str="100";
    console.log(parseInt(str));
    console.log(typeof parseInt(str));
    console.log(parseInt("3.14"));
     console.log(parseInt("3.12px"));   
     console.log(parseFloat('3.13px'));
      console.log(parseFloat('3.13'));
      console.log(Number(str));
      console.log('3'-2);
      console.log('90'-80);
      console.log('80'*80);
    </script>
</body>
</html>